2.1.2. Classification System

As shown in Table 2, according to the importance of ecological functions, ecological space is further subdivided into four secondary categories: restricted ecological space (ER), priority ecological space (EP), general ecological space (EG), and accommodated ecological space (EA). Restricted ecological space refers to areas that perform important ecological functions and require restricted protection, including national nature reserve areas with extremely important ecological services, first-class rivers (including waters in the land cover data collection), and extremely sensitive ecological areas.

**Table 2.** Relationship between the classification system of PLE spaces and MLC classification.


According to different production functions, the production space is divided into industrial production space (PI) and agricultural production space (PA). Based on GDP and NPP, the agricultural production space is further subdivided into priority agricultural production space (PP) and general production space (PG). The economic value (GDP) and net primary productivity (NPP) are evaluated, and those that are higher than the average GDP or NPP are regarded as priority agricultural production spaces, and the others are regarded as general agricultural production spaces. General agricultural production space and general ecological space give priority to land conversion in the subsequent optimization process.
